POISONOUS AND INJURIOUS PLANTS =p 
normal cultivation practices used in flower and vegetable gardens, 
provision grounds,‘ and cultivated fields. 
Pulling toxic plants or grubbing with handtools is practicable where 
small numbers occur in limited areas, especially where inaccessible to 
machinery or where other plants might be damaged by using 
herbicides. Clipping or brushchopping pastures, though desirable for 
other reasons, is not usually practical as the only method for weed 
control, because so many woody perennials sprout following cutting. 
Except where the vegetation is too dense for any other method, use 
of a bulldozer, even for initial clearing, should be avoided, because 
of the excessive amount of topsoil removed, and the high cost. Re- 
growth and seed sprouting occur as with brushchopping. 
A single fire is seldom effective in controlling any species of plant, 
and repeated burning is detrimental to pastures. The danger of fire 
getting out of hand is also a strong reason for not using it. On the 
other hand, flame throwers, used when the pasture is too green to burn, 
might be valuable against certain plants in limited areas. 
Biological control is the destruction of plants by disease or insects. 
It is harder than it sounds to find an insect that will kill the plant you 
wish to control without damaging other vegetation. Insects have been 
used for biological control only on a limited scale in the continental 
United States. However, this type of control has been used very 
effectively against pricklypear in Australia and Nevis, British West 
Indies; against St. John’s Wort in the continental United States; and 
against certain woody weeds in Hawaii. Biological weed control in 
the Virgin Islands is being investigated. 
Chemical control of poisonous plants is probably the most generally 
successful of the three methods, and has become a widespread practice 
throughout the world since World War II. The selective herbicides 
such as 2,4-D and 2,4,5-T are practically nontoxic to humans and 
livestock, noncorrosive, comparatively inexpensive, and easily applied 
as a spray, and they are effective against many poisonous plants. 
Chemical control, by low volatile selective herbicides, should be used 
on weeds, including toxic ones, where they occur in pastures or other 
areas accessible to livestock, provided necessary precautions against 
harm to other plants are used. Specific recommendations for some of 
the common poisonous plants are given under “Management and 
Control.” 
Complete eradication is seldom attained with a single application of 
a herbicide, especially with so-called hard-to-kill species like Maran 
(Croton discolor Willd.), for example. Even susceptible species may 
need several applications because of plants that may have been missed, 
regrowth from roots and stumps, and germination of seeds. Poison- 
ous plants are often adequately controlled by regular weed control 
operations aimed at the commoner, nonpoisonous weeds. 
*A provision ground is a cane field, or part of one, on which the cane has run 
out and after being plowed and “banked” is turned over to the Estate’s laborers 
for 1 year before it is replanted to cane. Most of this area goes into root crops, 
such as true yams (Dioscorea), sweetpotatoes, sweet and bitter cassava, tannias, 
eddoes, or dasheens. There are also field corn, okra, pigeon and cow peas, 
peanuts, dill, and perhaps other vegetables. The kinds of weeds and other casual 
plants are determined (1) by the land’s having just been in sugarcane; (2) by 
the high banks and deep furrows; and (3) by the preponderance of root crops 
and the type of cultivation used for them. 
